Abstract:
Type 2 diabetes mellitus (T2DM) adversely affects the normal functioning, intrinsic material
properties, and structural integrity of many tissues, including bone. It is well known that the
clinical utility of areal bone mineral density (aBMD) is limited to assess bone strength in individuals with T2DM. Therefore, there is a need to explore new diagnostic techniques that can
better assist and improve the accuracy of assessment of bone tissue quality. The present
study investigated the link between bone and fingernail material/compositional properties in
type 2 diabetes mellitus (T2DM). For that, femoral head and fingernail samples were
obtained from twenty-five adult female patients (with/without T2DM) with fragility femoral
neck fractures undergoing hemi/total hip arthroplasty. Cylindrical cores of trabecular bone
were subjected to micro-CT, and lower bone volume fraction was observed in the diabetic
group than the non-diabetic group due to fewer and thinner trabeculae in individuals with
T2DM. The material and compositional properties of bone/fingernail were estimated using
nanoindentation and Fourier Transform Infrared Spectroscopy, respectively. Both bone/fingernails in T2DM had lower reduced modulus (Er), hardness (H), lower Amide I and Amide II
area ratio (protein content), higher sugar-to-matrix ratio, and relatively high carboxymethyllysine (CML) content compared with non-diabetic patients. Sugar-to-matrix ratio and relative
CML content were strongly and positively correlated with HbA1c for both bone/fingernail.
There was a positive correlation between bone and fingernail glycation content. Our findings
provide evidence that the degradation pattern of bone and fingernail properties go hand-inhand in individuals with T2DM. Hence, the fingernail compositional/material properties
might serve as a non-invasive surrogate marker of bone quality in T2DM; however, further
large-scale studies need to be undertaken.
